Base station, communication control method, and wireless communication system

Abstract

A base station includes an obtaining unit and an instructing unit. The obtaining unit obtains, from another base station that communicates with a mobile device, a propagation delay amount between the other base station and the mobile device. When a propagation delay amount between the base station and the mobile device which is based on the propagation delay amount obtained by the obtaining unit is present within a predetermined range from a boundary of a detecting window that is used in detecting a preamble sequence transmitted from the mobile device, the instructing unit instructs the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window that lies adjacent across the boundary.

What is claimed is: 
     
       1. A base station comprising:
 an obtaining unit that obtains, from another base station that communicates with a mobile device, a propagation delay amount between the other base station and the mobile device; and 
 an instructing unit that, when a propagation delay amount between the base station and the mobile device which is based on the propagation delay amount obtained by the obtaining unit is present within a predetermined range along a forward direction of a time axis from a boundary at the beginning of a detecting window that is used in detecting a preamble sequence transmitted from the mobile device, instructs the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in a backward direction of the time axis, adjacent across the boundary at the beginning of the detecting window and that, when the propagation delay amount is present within the predetermined range along the backward direction of the time axis from a boundary at the end of the detecting window, instructs the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in the forward direction of the time axis, adjacent across the boundary at the end of the detecting window. 
 
     
     
       2. The base station according to  claim 1 , further comprising:
 an estimating unit that estimates the propagation delay amount between the base station and the mobile device based on the propagation delay amount obtained by the obtaining unit; and 
 a determining unit that determines whether or not an estimated propagation delay amount that is the propagation delay amount estimated by the estimating unit is present within a predetermined range from the boundary of the detecting window that is used in detecting a preamble sequence transmitted from the mobile device, wherein 
 when the determining unit determines that the estimated propagation delay amount is present within the predetermined range from the boundary of the detecting window, the instructing unit instructs the mobile device to stop the transmission of the preamble sequence corresponding to the other detecting window which lies adjacent across the boundary. 
 
     
     
       3. The base station according to  claim 1 , further comprising a detecting unit that detects a preamble sequence, which is transmitted from the mobile device, using the detecting window, wherein
 apart from instructing the mobile device to stop the transmission of the preamble sequence corresponding to the other detecting window, the instructing unit instructs the detecting unit to stop the detection of a preamble sequence using the other detecting window. 
 
     
     
       4. The base station according to  claim 2 , wherein, the estimating unit estimates the propagation delay amount between the base station and the mobile device by calculating a tentative propagation delay amount by subtracting the propagation delay amount obtained by the obtaining unit from a propagation delay amount between the other base station and the base station and correcting the tentative propagation delay amount using a correction coefficient that is set in advance corresponding to overlapping sectors between the other base station and the base station. 
     
     
       5. A communication control method comprising:
 obtaining, by a base station, from another base station that communicates with a mobile device, a propagation delay amount between the other base station and the mobile device; 
 transmitting, by the base station, when a propagation delay amount between the base station and the mobile device which is based on the propagation delay amount obtained at the obtaining is present within a predetermined range along a forward direction of a time axis from a boundary at the beginning of a detecting window that is used in detecting a preamble sequence transmitted from the mobile device, 
 a signal as an instruction to the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in a backward direction of the time axis, adjacent across the boundary at the beginning of the detecting window and transmitting, by the base station, when the propagation delay amount is present within the predetermined range along the backward direction of the time axis from a boundary at the end of the detecting window, a signal as an instruction to the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in the forward direction of the time axis, adjacent across the boundary at the end of the detecting window; and 
 receiving, by the mobile device, the signal that is transmitted by the base station as the instruction to stop the transmission of the preamble sequence. 
 
     
     
       6. A wireless communication system comprising:
 a base station; and 
 a mobile device, wherein 
 the base station includes
 an obtaining unit that obtains, from another base station that communicates with the mobile device, a propagation delay amount between the other base station and the mobile device; and 
 a wireless transceiving unit that, when a propagation delay amount between the base station and the mobile device which is based on the propagation delay amount obtained by the obtaining unit is present within a predetermined range along a forward direction of a time axis from a boundary at the beginning of a detecting window that is used in detecting a preamble sequence transmitted from the mobile device, transmits a signal as an instruction to the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in a backward direction of the time axis, adjacent across the boundary at the beginning of the detecting window and that, when the propagation delay amount is present within the predetermined range along the backward direction of the time axis from a boundary at the end of the detecting window, transmits a signal as an instruction to the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in the forward direction of the time axis, adjacent across the boundary at the end of the detecting window, and 
 
 the mobile device includes a receiving unit that receives the signal that is transmitted by the base station as the instruction to stop the transmission of the preamble sequence. 
 
     
     
       7. A base station comprising:
 a processor; and 
 a memory, wherein the processor executes: 
 obtaining, from another base station that communicates with a mobile device, a propagation delay amount between the other base station and the mobile device; 
 instructing, when a propagation delay amount between the base station and the mobile device which is based on the propagation delay amount obtained at the obtaining is present within a predetermined range along a forward direction of a time axis from a boundary at the beginning of a detecting window that is used in detecting a preamble sequence transmitted from the mobile device, 
 the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in a backward direction of the time axis, adjacent across the boundary at the beginning of the detecting window; and 
 instructing, when the propagation delay amount is present within the predetermined range along the backward direction of the time axis from a boundary at the end of the detecting window, the mobile device to stop the transmission of the preamble sequence corresponding to another detecting window which lies, in the forward direction of the time axis, adjacent across the boundary at the end of the detecting window.